Danfoss VLT series Service Manual

5-18
VLT is a registered Danfoss trademark
With a phase loss, the current waveform of the remaining
phases would take on the appearance shown in Figure 5-11.
Figure 5-11. Input Current Waveform with Phase Loss
Always verify the condition of the input voltage waveform before
forming a conclusion. The current waveform will follow the
voltage waveform. If the voltage waveform is incorrect proceed
to investigate the reason for the AC supply problem. If the
voltage waveform on all three phases is correct but the current
waveform is not then the input rectifier circuit in the drive is
suspect. Perform the static soft charge and rectifier tests and
also the dynamic SCR/Diode module test.

Danfoss VLT series Specifications

General

Series	VLT
Category	DC Drives
Output Voltage	0-100% of input voltage
Protection Features	Overvoltage, Undervoltage, Overcurrent, Overtemperature, Short Circuit, Ground Fault
Communication Interfaces	Profibus, CANopen
Enclosure Rating	IP20, IP21, IP55, IP66
Cooling Method	Forced Air Cooling, Convection Cooling
Control Mode	Sensorless Vector, Closed Loop Vector
Ambient Temperature	-10°C to +50°C (14°F to 122°F)